The port is automatically determined if it is omitted and the URI scheme is known.

Library Procedures

This library replaces most of the procedures in uri-generic. If you need to work with URIs on the uri-generic level or need to work with both uri-generic and uri-common URI objects, you will have to import and prefix or rename procedures.

Constructors and predicates

These constructors fully decode their arguments, so afterwards it is impossible to distinguish between encoded delimiters and unencoded delimiters. This makes uri-common objects decoding endpoints; no further decoding on the URI level is possible (of course, applications are free to decode further information inside the URI). If for some reason, the original URI is still needed, it can be converted to a uri-generic. However, updating a URI component causes this component's original encoding to be lost, so be careful!

[procedure](uri-reference STRING) => URI

A URI reference is either a URI or a relative reference (RFC 3986, Section 4.1). If the given string's prefix does not match the syntax of a scheme followed by a colon separator, then the given string is parsed as a relative reference.

[procedure](absolute-uri STRING) => URI

Parses the given string as an absolute URI, in which no fragments are allowed. If no URI scheme is found, or a fragment is detected, this raises an error.

Absolute URIs are defined by RFC 3986 as non-relative URI references without a fragment (RFC 3986, Section 4.2). Absolute URIs can be used as a base URI to resolve a relative-ref against, using uri-relative-to (see below).

Predicates

There are several predicates to check whether objects are URI references (the most general type of an URI-like object), or more specific types of URIs like absolute URIs or relative references. The classification tree of URI-like objects looks a bit like this:

Is the given object a URI reference? All objects created by URI-common constructors are URI references; they are either URIs or relative references. The constructors below are just more strict checking versions of uri-reference. They all create URI references.

[procedure](absolute-uri? URI) => BOOL

Is the given object an absolute URI?

[procedure](uri? URI) => BOOL

Is the given object a URI? URIs are all URI references that include a scheme part. The other type of URI references are relative references.

[procedure](relative-ref? URI) => BOOL

Is the given object a relative reference? Relative references are defined by RFC 3986 as URI references which are not URIs; they contain no URI scheme and can be resolved against an absolute URI to obtain a complete URI using uri-relative-to.

[procedure](uri-path-absolute? URI) => BOOL

Is the URI's path component an absolute path?

[procedure](uri-path-relative? URI) => BOOL

Is the URI's path component a relative path?

[procedure](uri-default-port? URI) => BOOL

Is the URI's port the default port for the URI's scheme?

Reference Resolution

[procedure](uri-relative-to URI URI) => URI

Resolve the first URI as a reference relative to the second URI, returning a new URI (RFC 3986, Section 5.2.2).

[procedure](uri-relative-from URI URI) => URI

Constructs a new, possibly relative, URI which represents the location of the first URI with respect to the second URI.

Encode or decode an alist using the encoding corresponding to the form-urlencoded media type, using the given separator character(s).

The alist contains key/value pairs corresponding to the values in the final urlencoded string. If a value is #f, the key will be omitted from the string. If it is #t the key will be present without a value. In all other cases, the value is converted to a string and urlencoded. The keys are always converted to a string and urlencoded.

When encoding, if separator is a string, the first character will be used as the separator in the resulting querystring. If it is a char-set, it will be converted to a string and its first character will be taken. In either case, all of these characters are encoded if they occur inside the key/value pairs.

When decoding, any character in the set (or string) will be seen as a separator.

The separator defaults to the string ";&". This means that either semicolons or ampersands are allowed as separators when decoding an URI string, but semicolons are used when generating strings.

If you would like to use a different separator, you should parameterize all calls to procedures that return an uri-common object.

String encoding and decoding

A little more generic but also more level than encoding/decoding whole query strings/alists at a time, you can also encode and decode strings on an individual level.

[procedure](uri-encode-string STRING [CHAR-SET]) => STRING

Returns the percent-encoded form of the given string. The optional char-set argument controls which characters should be encoded. It defaults to the complement of char-set:uri-unreserved. This is always safe, but often overly careful; it is allowed to leave certain characters unquoted depending on the context.

[procedure](uri-decode-string STRING [CHAR-SET]) => STRING

Returns the decoded form of the given string. The optional char-set argument controls which characters should be decoded. It defaults to char-set:full.

Normalization

[procedure](uri-normalize-case URI) => URI

URI case normalization (RFC 3986 section 6.2.2.1)

[procedure](uri-normalize-path-segments URI) => URI

URI path segment normalization (RFC 3986 section 6.2.2.3)

uri-generic, string and list representation

To convert between uri-generic and uri-common objects, use these procedures. As stated above, this will allow you to retrieve the original encoding of the URI components, but once you update a component from the uri-common side, the original encoding is no longer available (the updated value replaces the original value).

[procedure](uri->string uri-common [userinfo]) => string

Reconstructs the given URI into a string; uses a supplied function LAMBDA USERNAME PASSWORD -> STRING to map the userinfo part of the URI. If not given, it represents the userinfo as the username followed by ":******".

[procedure](uri->list URI USERINFO) => LIST

Returns a list of the form (SCHEME SPECIFIC FRAGMENT); SPECIFIC is of the form (AUTHORITY PATH QUERY).

Character sets

As a convenience for further sub-parsers or other special-purpose URI handling code like separately URI-encoding strings, there are a couple of character sets exported by uri-common.

License

Copyright 2008-2010 Peter Bex
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